Lawn edge trimmer



Jan. 12, 1954 A. T. DUDLEY LAWN EDGE TRIMMER Filed May 51 195o JNVENToR./VDPEW T. Dl/DLEY BY/ Patented Jan. 12, 1 954 UNITED 'STATES PATENTAOFFICE l2,665,540 y v l LAWN EDGE TRIMMEn ndewT. udley, PotArthur, Tex.

' Application MayfSl, 1950, Serial No. 165,341

The present invention relates to. a cutting Jde-V Extending upwardly atan appropriate anglefifrom I the fra-me is a handlethat adaptsthe-devicefor manual operation.I Journall'ed in the. frame vis a drive shaft whichis connected throughappropriate gearing to the drive wheel and whichcarries yat itsouter freegend4 a cutter wheel. A xed cutter is alsosecured to the frame .inposition for cooperation with the cuttingwheel.r

An `important object of the invention. is `to provide, in a lawn trimmerof the character 5de.- scribed, a pinion which is` mounted onthe driveshaftV by one-way clutch mechanism 'whereby the driving relationbetweenthis. pinion and the drive shaft is established for only onedirecti'onofretation. In the opposite directionthepinion ro?- tates freely `withrespect t0 the. drive shaft. rlhis pinion meshes with an internal ringgearcarried by the drive wheel. and establishesfthe driveto the driveshaft. With this arrangement the'lawn trimmer may be moved in onedirection to rotate the cutter wheel while movement in the oppositedirection is permitted without: .being-accompanied by any rotation ofthe'cutter wheel. Another highly important object 'Lof thermes,- entinvention is to provide, in al'awn trimmer of the type indicated, ay xedcutter which Lincludes three shear blades or cutting elements .lo catedat different levels. t These shear blades: are adapted to Vcooperatewith the shear elementson the cutting wheel, and their location' at thethree levels assures of a complete and eiii'cient cutting ofthe grassalong the edges ofthe lawn;

Still another object is-torprovidey-in arlawn trimmer of the f characternoted, a xe'd cutter which includes a portion that projects below `theIowermost point of the cuttingwheel. This portion serves as a guide suchas 'may extend down below the edge of a concrete walk or similarstructure usually found along the-edge ofalawn. Y Yetanther object'efthe invention'is to provide, in a lawn trimmer ofthe typelaforesaid; acutting wheel that is dri'vably mounted .on Vthe drive shaft and whichis formed with a plurality oficutting elements which are-s'ospae'edabout the'y periphery of the cutting wheel thationlyl one f them is in`eieetive"engagementwith4 one ef the shear velements on the xed cutterat one time. With this arrangement definite assurance is had that thelawn trimmer will, at any one time,l be l.subjected only to the load ofa single cutting operation.

k A further object of the invention is to provide, in a lawn cutterofthe type noted, a cutting wheel having cutting elements which areslightly greater in extent than at least two ofthe shear elements on thefixed cutter. This overlapping relationprovides for drawing inofthegrass `onto these elements of the xedbcutter.

Another highly important robject of the inven-l tion is to provide, inai lawn trimmer` of the type indicated, a xed cutterhavingshearelements, the cutting edgesr of which are angularly offsetwith respect to true radii, together .with a cutting wheel havingcutting elements the edges or which are radially disposed. This olsetrelation, coupled with thetrue radial position of the edges of thecutting elements of the cutting wheel, provides fora shearing actioninthe actual cutting operation. I

Various other more detailed objects and advantages of the invention,such as arise in con# nection with carrying out the above-noted ideas pina practicalembodiment, will in part become* appa-rent and in part behereinafter stated as the, description of the invention proceeds. y

The invention therefore comprises a lawn trimmer-including a framecarrying an axle ori which a driving wheel is mounted, with the driv-ting wheel carrying a ringvgear that meshes with a pinion that is mountedthrough the medium of a one-.way clutch on a drive shaft that isjournalled in the frame. The frame carries a iixed cutter having threeshear elements located at different levels, with the edges ofthe shearelements angularly offset with respect to radii from the axis of thedrive shaft, Y y

- Drivably mountedon the drive shaft is a` cutter wheel having aplurality ofcutting elements greater in number than those on the iixedycut-- ter and so arranged with respect theretozthat only one cuttingelement ofthe cuttingfwheel engages a shear element of the fixed cutterat one time. The edges of the cutting elements on the cutting wheel arein alignment with the true radii of the axis of the drive shaft and theyare longer than at least two of the shearelements of the fixed cutter. lY l Y TheV lowermost shear element of the fixed cutter is extended belowthe drive wheel to function as la guide. l

Fora-full anda more complete understanding of the invention, referencemay be had to the following description and accompanying drawing,wherein:

Figure 1 is a view in side elevation of a lawn trimmer designed inaccordance with the precepts of this invention. In this view the handleis broken away.

Figure 2 is a view in end elevation of the lawn trimmer shown in Figure1;

Figure 3 is a view looking from the top showing most of the frame anddriving wheel in horizontal section;

Figure 4 is an enlarged detailed view taken from the side with partsbroken away and shown in section of the driven wheel and brings out theone-way clutch which is interposed between the pinion and the drivenshaft;

Figure 5 is an enlarged detailed perspective of the frame per se; and

Figure 6 is an enlarged detailed perspective of the fixed cutter.

Referring now to the drawing, wherein like characters of referenceindicate corresponding parts and, first, more particularly to Figure 5,the lawn trimmer of this invention is shown as including a frame whichis referred to in its entirety by the reference character F. The frame Fcomprises a circular plate I which is formed with a central opening IIwhich is threaded. The plate IB is slightly thickened or embossed aboutthe opening II on its inner face as shown at I2 in Figure 3. On itsouter face the plate I6 carries a channel-shaped member I3 which isdesigned to receive one leg of an L-shaped bracket that is shown at I4in Figure 2. A countersunk screw such as represented at II in Figure 2may be employed to secure the bracket I4 in position. The bracket I4carries a socket member i6 which receives a handle I'I in a well-knownmanner.

Included as a part of the frame F is a sectorlike plate I8, and anopening I9 extends through the plate I0, the sector-like portion I8, anda ring-like embossment 20 that is disposed about the opening I9.

A iixed cutter is shown at Figure 6 and is referred to in its entiretyby the reference character C. The xed cutter C is formed with an openingat 2l which receives the ring-like embossment 20. The sector I8 isformed with a plurality of openings 22 and 22a, and the fixed cutter Cis formed with a plurality of openings 23 and 23a which are similarlyarranged so that they align with the openings 22 and 22a. Screw boltsrepresented at 9 in Figure 3 secure the fixed cutter C in position onthe sector I8.

The xed cutter C is provided with three shear elements designated 24,25, and 26. Each of these cutting elementsl has a bevelled cutting edgewhich is angularly oiset with respect to a radius taken from the axis ofthe opening 2|. It will be noted that the lowermost cutting element 26is longer than the cutting elements 24 and 25 for a purpose to be laterdescribed.

Secured in the opening I I is an axle 21. Freely journalled on the axle21 is a drive wheel which is referred to in its entirety by thereference character D. This drive wheel D includes a cylindrical wall 28that is adapted to roll along the edge of a walk or pavement and whichis integrally connected to a circular plate 23. The latter is formedwith a central enlargement at 3B which is continued inwardly throughoutthe entire axial extent of the wheel D and an opening 3l extends throughthis enlargement and the plate 29. It is this opening 3I which receivesthe 4 axle 21. A washer 32 and a cotter pin 33 secure the drive wheel Din position on the axle 21.

Mounted on the inner face of the circular plate 29 of the drive Wheel Dis an internal ring gear 34. This ring gear may be held in position onthis inner face in any preferred manner such as by the screw bolts shownat 35.

Meshing with the ring gear 34 is a pinion 36 which is connected, throughthe medium of the one-way clutch mechanism shown at 31 in Figure 4, to adriven shaft 38. The one-way clutch 31 serves to establish the drivingrelation between the pinion 36 and the driven shaft 3B in one directionof rotation.

The driven shaft 38 is journalled in the opening i3 and extends beyondthe outer face of the fixed cutter C. It carries a hub 33, and securedto this hub 39 is a cutting wheel 4U. The cutting wheel 40 is secured tothe hub 39 in any preferred manner, such as by the screw boltsrepresented at 4I.

The cutting wheel 40 is provided with a plurality of cutting elements42. The number of these cutting elements 42 should be in excess of thethree shear elements on the xed cutter C. In the form of the inventionillustrated in the drawing, the cutting wheel 4I) is shown as having sixof the cutting elements 42. Each of these cutting elements 42 has anedge 43 that is disposed in alignment with a true radius taken from theaxis of the driven shaft. Thus, these cutting edges 43 cooperate Withthe cutting edges of the elements 24, 25, and 26 of the xed cutter witha shearing action.

While the cutting elements 42 are equi-angularly spaced about thecutting wheel 40, the elements 24, 25, and 26 are so arranged that onlyone of the cutting edges 43 is in engagement with any one of them at anyone time. Thus, the machine is never subject to a load any greater thanthat of a single cutting operation.

As shown in Figure 1, the cutting element 26 extends below the lowermostperiphery of the driving wheel D whereby it is adapted to function as aguide which will extend down along the edge of a concrete walk. It isalso notable that the cutting edges 43 are slightly longer than thecutting edges of the members 24 and 25.

Operation While the operation of the above described lawn trimmer isbelieved to be obvious from the description of the parts given, it maybe briefly outlined by noting that the operator avails of the handle I1in a `lwell-known manner and pushes the drive wheel D along the surfaceat the edge of a lawn. During this operation the member 26 whichprojects below the edge of the walk will function as a guide. As thedriving Wheel D is rotated the ring gear 34 is correspondingly rotatedand drives the pinion 36. The latter, through the medium of the onewayclutch 31 drives the driven shaft 38. Due to the gear ratio, the drivenshaft 38 is rotated four times for every complete revolution of thedrive wheel D. That is, the gear ratio is four to one. The cutter wheel40 being drivably mounted on the driven shaft 38 is rotated so that theedges 43 of the cutting elements 42 are brought into successivecooperation with the cutting elements 24, 25, and 26. As aboveexplained, only one cutting operation actually takes place at any onetime. Due to the location of the cutting elements 24, 25, and 26 atdifferent levels, the edge of the lawn is eiectively trimmed as all thegrass therealong will be cut. Each cutting operation takes place with ashearing action due to the angular disposition of the cutting edges ofthe elements the latter iwill tend to draw grass down onto the cuttingelements 26, 25, and 26.

While a preferred specific embodiment of the invention is hereinbeforeset forth, it is to be clearly understood that the invention is not tobe limited to the exact mechanisms, constructions and devicesillustrated and described because Various modifications of these detailsmay be provided in putting the invention into prac- 24, 25, and 26 anddrive wheel. and a cutting wheel carried by said drive shaft and havingsix` cutting elements the cutting redges of which are in alignment withradii 'of said wheel and which have a radial eX- tent greater than thetwo shorter elements olf said xed cutter, the cutting elements of saidfixed cutter being spaced apart so thatV only one of them is ineffective engagement with the cutting element of the cutting Wheel atany onev time, each of the cutting elements on the cutting wheel havingan extent whereby it also extends below the lovrermost periphery of saiddrive wheel when it engages said lowermost xed cutter.v

ANDREW T. DUDLEY.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 223,505 Hanley Jan. 13, 1880 536,497 Warren Mar. 26, 1895856,940 Cady June 11, 1907 1,169,002 Butler Jan. 18, 1916 1,912,893Engel June 6, 1933 1,970,827 Van Kesteren Aug. 21, 1934 2,512,132 AyersJune 20, 1950

